THE PARA RUBBER TREE 117 



Federated Malay States the wild passion-flower {Passi- 

 flora joelida) has been utilised for the same pui'pose. 

 This plan has not come into general favour, and experi- 

 ments have shown that the growth of such cover-crops 

 may retard the development of the trees. The method 

 is, however, still under trial in Malaya and Ceylon. 



Manuring. — A number of interesting trials have been 

 made on rubber estates to determme the effect of the 

 application of different classes of manines on the growth 

 of the Para tree, and the results so far obtained indicate 

 that the development of the young trees, including the 

 rate of increase in girth, can be greatly stimulated by the 

 judicious use of suitable fertilisers. Carefully controlled 

 experiments are, however, required before any definite 

 conclusions can be drawn. 



Diseases and Pests. — The exclusive cultivation of one 

 species of plant over large continuous areas offers very 

 favourable conditions for the rapid spread of any disease 

 or pest which may make its appearance, and some mis- 

 givings on this pomt have been felt m connection with the 

 extensive plantations of Hevea hrasiliensis in Malaya 

 and Ceylon. Fortunately, however, no serious trouble 

 has yet been experienced, and the only important disease 

 of the Para tree is that caused by the fungus Forms 

 semitostus, Berk., which attacks the roots. In Malaya 

 Avhite ants {Termes gestroi) have proved very troublesome 

 on many estates, and a few other insects, chiefly beetles 

 and crickets, do some damage in certain cases. It is 

 of interest to note that the occurrence of both Fomes 

 semitostus and white ants in rubber plantations is to be 

 traced to the presence in the ground of the decaying 

 stumps of the original trees which serve to infect the 

 rubber trees. 



Only a very brief notice of the principal fungoid 

 diseases which attack Hevea brasiliensis can be given 

 here, and for fuller information reference must be made 

 to the literature on the subject.* 



* The Physiology and Diseases of Hevea brasiliensis, by T. Fetch. 

 (London: Dulau & Co.). 



Annual Reports of the Ceylon Mycologist. 



Circulars of the Royal Botanic Gardens, Ceylon. 



Annual Reports of the Director of Agriculture and the Mycologist 

 in the Federated Malay States. 



Bulletins of the Department of Agriculture, Federated Malay States. 



